The present invention relates to control systems, and more particularly, to a method of robust multivariable predictive control (RMPC) techniques utilizing range controls.
In present day process control systems, many techniques are presently in use which utilize model predictive control techniques which control process variables to predetermined setpoints. Oftentimes the setpoints are a best estimate by the system operator of the value of the setpoint or set points. When a process is being controlled to a setpoint, the controller may not be able to achieve the best control performances, especially under process/model mismatch.
In order to enhance the controller performance, there is a need to provide a method for controlling a process which controls the process variables (i.e., controlled variables) by commanding each manipulated variable associated with the controller of the process control system to a corresponding range, i.e., each control specification having an upper bound and a lower bound, The result is that the Frobenius norm of the controller is minimized and thus the process is controlled within the desired tolerance of the product specification, the impact to the system is reduced, and results in a more robust controller.